final has 6 distinct synonyms spread across 4 of its 5 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
occurring at or forming an end or termination
“his concluding words came as a surprise”
an examination administered at the end of an academic term
Synonyms, antonyms and the broader and narrower relations for final come from Princeton University’s WordNet. Full sources and licences.